package com.xnew.encrypt;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;

/**   
* @Title: RSAEncrypt.java 
* @Description: TODO(RSA加密操作类) 
* @version V1.0   
*/
public class RSAEncrypt {

    /** 
     * 字节数据转字符串专用集合 
     */  
    private static final char[] HEX_CHAR = { '0', '1', '2', '3', '4', '5', '6',  
            '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };  
  
    private static RSAPublicKey publicKey = null;
	private static RSAPrivateKey privateKey = null;
	private static RSAEncrypt instance = null;
	private static final String path = RSAEncrypt.class.getProtectionDomain().getCodeSource().getLocation().getPath();
	
	private static String str = "测试字符串";
    
	static{
		try {
			String publicKeyByFile = RSAEncrypt.getInstace().loadPublicKeyByFile(path);
			publicKey = RSAEncrypt.getInstace().loadPublicKeyByStr(publicKeyByFile);
			String privateKeyByFile = RSAEncrypt.getInstace().loadPrivateKeyByFile(path);
			privateKey = RSAEncrypt.getInstace().loadPrivateKeyByStr(privateKeyByFile);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	private RSAEncrypt(){}
	
	public static RSAEncrypt getInstace(){
		if (instance == null) {
			instance = new RSAEncrypt();
		}
		return instance;
	}
	
    @SuppressWarnings("unused")
	public static void main(String[] args) throws Exception {
    	RSAEncrypt.getInstace().genKeyPair(System.getProperty("user.dir"));
    	String privateKeyEncrypt = RSAEncrypt.getInstace().privateKeyEncrypt(str);
    	String publicKeyDecrypt = RSAEncrypt.getInstace().publicKeyDecrypt(privateKeyEncrypt);
    	
	}
    
    /**
     * @Title: publicKeyEncrypt   
     * @Description: TODO 公钥加密
     * @param:  data 原始加密数据(type: String)
     * @return: String 返回加密明文
     * @throws
     */
    public String publicKeyEncrypt(String data){
    	String encode = null;
    	try {
			byte[] encrypt = encrypt(publicKey, data.getBytes());
			encode = Base64.encode(encrypt);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return encode;
    }
    
    /**
     * @Title: publicKeyDecrypt   
     * @Description: TODO 公钥解密
     * @param:  encryptData 加密数据(type: String)
     * @return: String 返回原始数据明文
     * @throws
     */
    public String publicKeyDecrypt(String encryptData){
    	String encode = null;
    	try {
			byte[] decode = Base64.decode(encryptData);
	    	byte[] decrypt = decrypt(publicKey, decode);
	    	encode = new String(decrypt);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return encode;
    }
    
    /**
     * @Title: privateKeyEncrypt   
     * @Description: TODO 私钥加密
     * @param:  data 原始加密数据(type: String)
     * @return: String 返回加密明文
     * @throws
     */
    public String privateKeyEncrypt(String data){
    	String encode = null;
    	try {
			byte[] encrypt = encrypt(privateKey, data.getBytes());
	    	encode = Base64.encode(encrypt);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return encode;
    }
    
    /**
     * @Title: privateKeyDecrypt   
     * @Description: TODO 私钥解密
     * @param:  encryptData 加密数据(type: String)
     * @return: String 返回原始数据明文
     * @throws
     */
    public String privateKeyDecrypt(String encryptData){
    	String encode = null;
    	try {
	    	byte[] decode = Base64.decode(encryptData);
	    	byte[] decrypt = decrypt(privateKey, decode);
	    	encode = new String(decrypt);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return encode;
    }
    
    /** 
     * 随机生成密钥对 
     */  
    private void genKeyPair(String filePath) {  
        KeyPairGenerator keyPairGen = null;  
        try {  
            keyPairGen = KeyPairGenerator.getInstance("RSA");  
        } catch (NoSuchAlgorithmException e) {  
            e.printStackTrace();  
        }  
        keyPairGen.initialize(1024,new SecureRandom());  
        KeyPair keyPair = keyPairGen.generateKeyPair();  
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();  
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();  
        try {  
            String publicKeyString = Base64.encode(publicKey.getEncoded());  
            String privateKeyString = Base64.encode(privateKey.getEncoded());  
            FileWriter pubfw = new FileWriter(filePath + "/publicKey.keystore");  
            FileWriter prifw = new FileWriter(filePath + "/privateKey.keystore");  
            BufferedWriter pubbw = new BufferedWriter(pubfw);  
            BufferedWriter pribw = new BufferedWriter(prifw);  
            pubbw.write(publicKeyString);  
            pribw.write(privateKeyString);  
            pubbw.flush();  
            pubbw.close();  
            pubfw.close();  
            pribw.flush();  
            pribw.close();  
            prifw.close();  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
    }  
  
    /** 
     * 从文件中输入流中加载公钥 
     * 
     * @param in 
     *            公钥输入流 
     * @throws Exception 
     *             加载公钥时产生的异常 
     */  
    private String loadPublicKeyByFile(String path) throws Exception {  
        try {  
            BufferedReader br = new BufferedReader(new FileReader(path  
                    + "publicKey.keystore"));  
            String readLine = null;  
            StringBuilder sb = new StringBuilder();  
            while ((readLine = br.readLine()) != null) {  
                sb.append(readLine);  
            }  
            br.close();  
            return sb.toString();  
        } catch (IOException e) {  
            throw new Exception("公钥数据流读取错误");  
        } catch (NullPointerException e) {  
            throw new Exception("公钥输入流为空");  
        }  
    }  
  
    /** 
     * 从字符串中加载公钥 
     * 
     * @param publicKeyStr 
     *            公钥数据字符串 
     * @throws Exception 
     *             加载公钥时产生的异常 
     */  
    private RSAPublicKey loadPublicKeyByStr(String publicKeyStr)  
            throws Exception {  
        try {  
            byte[] buffer = Base64.decode(publicKeyStr);  
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");  
            X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer);  
            return (RSAPublicKey) keyFactory.generatePublic(keySpec);  
        } catch (NoSuchAlgorithmException e) {  
            throw new Exception("无此算法");  
        } catch (InvalidKeySpecException e) {  
            throw new Exception("公钥非法");  
        } catch (NullPointerException e) {  
            throw new Exception("公钥数据为空");  
        }  
    }  
  
    /** 
     * 从文件中加载私钥 
     * 
     * @param keyFileName 
     *            私钥文件名 
     * @return 是否成功 
     * @throws Exception 
     */  
    private String loadPrivateKeyByFile(String path) throws Exception {  
        try {  
            BufferedReader br = new BufferedReader(new FileReader(path  
                    + "privateKey.keystore"));  
            String readLine = null;  
            StringBuilder sb = new StringBuilder();  
            while ((readLine = br.readLine()) != null) {  
                sb.append(readLine);  
            }  
            br.close();  
            return sb.toString();  
        } catch (IOException e) {  
            throw new Exception("私钥数据读取错误");  
        } catch (NullPointerException e) {  
            throw new Exception("私钥输入流为空");  
        }  
    }  
  
    private RSAPrivateKey loadPrivateKeyByStr(String privateKeyStr)  
            throws Exception {  
        try {  
            byte[] buffer = Base64.decode(privateKeyStr);  
            PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(buffer);  
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");  
            return (RSAPrivateKey) keyFactory.generatePrivate(keySpec);  
        } catch (NoSuchAlgorithmException e) {  
            throw new Exception("无此算法");  
        } catch (InvalidKeySpecException e) {  
            throw new Exception("私钥非法");  
        } catch (NullPointerException e) {  
            throw new Exception("私钥数据为空");  
        }  
    }  
  
    /** 
     * 公钥加密过程 
     * 
     * @param publicKey 
     *            公钥 
     * @param plainTextData 
     *            明文数据 
     * @return 
     * @throws Exception 
     *             加密过程中的异常信息 
     */  
    private byte[] encrypt(RSAPublicKey publicKey, byte[] plainTextData)  
            throws Exception {  
        if (publicKey == null) {  
            throw new Exception("加密公钥为空, 请设置");  
        }  
        Cipher cipher = null;  
        try {  
            // 使用默认RSA  
            cipher = Cipher.getInstance("RSA");  
            // cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());  
            cipher.init(Cipher.ENCRYPT_MODE, publicKey);  
            byte[] output = cipher.doFinal(plainTextData);  
            return output;  
        } catch (NoSuchAlgorithmException e) {  
            throw new Exception("无此加密算法");  
        } catch (NoSuchPaddingException e) {  
            e.printStackTrace();  
            return null;  
        } catch (InvalidKeyException e) {  
            throw new Exception("加密公钥非法,请检查");  
        } catch (IllegalBlockSizeException e) {  
            throw new Exception("明文长度非法");  
        } catch (BadPaddingException e) {  
            throw new Exception("明文数据已损坏");  
        }  
    }  
  
    /** 
     * 私钥加密过程 
     * 
     * @param privateKey 
     *            私钥 
     * @param plainTextData 
     *            明文数据 
     * @return 
     * @throws Exception 
     *             加密过程中的异常信息 
     */  
    private byte[] encrypt(RSAPrivateKey privateKey, byte[] plainTextData)  
            throws Exception {  
        if (privateKey == null) {  
            throw new Exception("加密私钥为空, 请设置");  
        }  
        Cipher cipher = null;  
        try {  
            // 使用默认RSA  
            cipher = Cipher.getInstance("RSA");  
            cipher.init(Cipher.ENCRYPT_MODE, privateKey);  
            byte[] output = cipher.doFinal(plainTextData);  
            return output;  
        } catch (NoSuchAlgorithmException e) {  
            throw new Exception("无此加密算法");  
        } catch (NoSuchPaddingException e) {  
            e.printStackTrace();  
            return null;  
        } catch (InvalidKeyException e) {  
            throw new Exception("加密私钥非法,请检查");  
        } catch (IllegalBlockSizeException e) {  
            throw new Exception("明文长度非法");  
        } catch (BadPaddingException e) {  
            throw new Exception("明文数据已损坏");  
        }  
    }  
  
    /** 
     * 私钥解密过程 
     * 
     * @param privateKey 
     *            私钥 
     * @param cipherData 
     *            密文数据 
     * @return 明文 
     * @throws Exception 
     *             解密过程中的异常信息 
     */  
    private byte[] decrypt(RSAPrivateKey privateKey, byte[] cipherData)  
            throws Exception {  
        if (privateKey == null) {  
            throw new Exception("解密私钥为空, 请设置");  
        }  
        Cipher cipher = null;  
        try {  
            // 使用默认RSA  
            cipher = Cipher.getInstance("RSA");  
            // cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());  
            cipher.init(Cipher.DECRYPT_MODE, privateKey);  
            byte[] output = cipher.doFinal(cipherData);  
            return output;  
        } catch (NoSuchAlgorithmException e) {  
            throw new Exception("无此解密算法");  
        } catch (NoSuchPaddingException e) {  
            e.printStackTrace();  
            return null;  
        } catch (InvalidKeyException e) {  
            throw new Exception("解密私钥非法,请检查");  
        } catch (IllegalBlockSizeException e) {  
            throw new Exception("密文长度非法");  
        } catch (BadPaddingException e) {  
            throw new Exception("密文数据已损坏");  
        }  
    }  
  
    /** 
     * 公钥解密过程 
     * 
     * @param publicKey 
     *            公钥 
     * @param cipherData 
     *            密文数据 
     * @return 明文 
     * @throws Exception 
     *             解密过程中的异常信息 
     */  
    private byte[] decrypt(RSAPublicKey publicKey, byte[] cipherData)  
            throws Exception {  
        if (publicKey == null) {  
            throw new Exception("解密公钥为空, 请设置");  
        }  
        Cipher cipher = null;  
        try {  
            // 使用默认RSA  
            cipher = Cipher.getInstance("RSA");  
            // cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());  
            cipher.init(Cipher.DECRYPT_MODE, publicKey);  
            byte[] output = cipher.doFinal(cipherData);  
            return output;  
        } catch (NoSuchAlgorithmException e) {  
            throw new Exception("无此解密算法");  
        } catch (NoSuchPaddingException e) {  
            e.printStackTrace();  
            return null;  
        } catch (InvalidKeyException e) {  
            throw new Exception("解密公钥非法,请检查");  
        } catch (IllegalBlockSizeException e) {  
            throw new Exception("密文长度非法");  
        } catch (BadPaddingException e) {  
            throw new Exception("密文数据已损坏");  
        }  
    }  
  
    /** 
     * 字节数据转十六进制字符串 
     * 
     * @param data 
     *            输入数据 
     * @return 十六进制内容 
     */  
    @SuppressWarnings("unused")
	private String byteArrayToString(byte[] data) {  
        StringBuilder stringBuilder = new StringBuilder();  
        for (int i = 0; i < data.length; i++) {  
            // 取出字节的高四位 作为索引得到相应的十六进制标识符 注意无符号右移  
            stringBuilder.append(HEX_CHAR[(data[i] & 0xf0) >>> 4]);  
            // 取出字节的低四位 作为索引得到相应的十六进制标识符  
            stringBuilder.append(HEX_CHAR[(data[i] & 0x0f)]);  
            if (i < data.length - 1) {  
                stringBuilder.append(' ');  
            }  
        }  
        return stringBuilder.toString();  
    }  
	
}
